This invention relates generally to musical instruments and more particularly to those electronic instruments which are termed music synthesizers in which the sound waveforms are generated completely electronically with no mechanically vibrating elements contributing to the sound.
Music synthesizers are usually controlled primarily by means of a piano-type keyboard with sufficient keys to allow the production of at least one octave of the chromatic equally tempered scale. In the usual case, actuation of a key initiated the operation of a so-called "function generator" whose output voltage waveform, delineated by auxiliary control presets, causes the "attack" or fading in of the tone corresponding to the key pressed, and also the "decay" or fading out of the tone. The timbre or overtone content of the sound is similarly preset and not under the direct control of the actuating element.
The present invention, while an electronic music synthesizer, does not utilize a full keyboard for pitch control, but is a stringed instrument with a key associated with each string.
The purpose of the present invention is to make possible the accurate simulation of acoustic instruments, with their wide tonal coloration and ability to respond to the individual musician's "feeling".
To accomplish this, it is necessary that the qualities of pitch, timbre, and loudness be controlled in real time, that is not a preset quality as with a discrete tone fretboard or preset timbre and loudness control but under continuous control of the performer.
Toward this end, a fretless fingerboard is used in order that the widest possible range of pitch control can be realized. True vibrato and portamento can be accomplished as pitch change is continuous as with a violin.
Control of timbre and loudness is provided by a piano-like key for each string. The degree of actuation of this key directly controls the loudness and timbre or overtone content of the sound produced.
All synthesizers produce sounds by means of several basic waveforms, square waves, basis for reed instruments; ramps, basis for horns; triangular waveforms, basis for flute or piccolo sounds; or pulses, basis for violin, cello, etc. sounds. Filters, either fixed or pitch-following, shape these waveforms by subtractive synthesis to simulate those aforementioned instruments. These same type wave generating and shaping circuits are utilized in this invention although somewhat modified due to the novel pitch-controlling elements, i.e., the resistance strings.
The prior art does not disclose an electronic musical instrument which affords accurate, repeatable real-time control of timbre and loudness. Thus, U.S. Pat. No. 3,223,771 discloses an instrument utilizing a fingerboard where conductive strings are fingered into contact with an underlying continuous resistance element to provide continuous pitch change, but the instrument lacks the timberal control required for proper acoustic instrument simulation. Similarly, U.S. Pat. No. 4,235,141 discloses a fretless fingerboard which can control the instrument pitch in a continuous manner but here also continuous control of timbre is lacking.
U.S. Pat. No. 4,306,480 discloses an instrument intended for a toy which utilizes the fretboard-ladder resistor means of controlling pitch wherein a means is provided for controlling the pitch between fretted pitches by "bending" or swaying the strings as used by guitar players. Additionally, a "touch-responsive" control for providing glides of loudness and timbre is shown. However, this means shown is not intended for accurate or repeatable control of timbre and loudness as these qualities will depend upon the electrical resistance of the performers fingers, a value which varies widely with temperature, humidity, state of health, frame of mind, etc. Further, the contact resistance varies with slight finger pressure changes rendering accuracy impossible.
It is therefore an object of the present invention to provide an electronic musical instrument which is capable of attaining the tonal coloration and "feeling" of an accoustic instrument.
It is a further object of the invention to provide an electronic musical instrument wherein the pitch, timbre and loudness of each sound can be controlled by the performer in real time in an accurate and repeatable manner as the instrument is being played.
It is a further object of the invention to provide an electronic instrument having string members which simulate the strings of an accoustic string instrument and in which effects such as true vibrato and portamento can be attained by the performer.
In accordance with the invention, the above objects are accomplished by providing an electronic musical instrument having a plurality of string-like playing members which simulate the strings of an accoustic instrument and wherein sounds of varying pitch are produced at different positions along their length, which includes audio oscillator means associated with each string-like member for producing a frequency-controllable audio output signal, means responsive to a control signal for varying the overtone content and amplitude of the audio output signal, and means accessible to the performer and capable of being moved to different control positions for providing the control signal to control the timbre and loudness of each sound as its being produced. In the preferred embodiment, the means for providing the control signal includes a light source and photoresponsive means and movable means for controlling the amount of light which is incident on the photoresponsive means.